Data storage on magnetic tape is well known and tape recorders have been used to record data tracks on magnetic tape. Traditionally, data are recorded in a plurality of parallel data tracks on the magnetic tape. The read/write or recording head is then positioned relative to the tape by moving the head to different track positions as desired. In such a system, the tape tracks are generally sufficiently wide and separated to facilitate reliably reading and writing the data.
Recording heads for a tape system may be similar in design and operation to recording heads for disk drives. A recording head may have one or more write elements and one or more read elements for writing and reading data, respectively. FIG. 11 shows in schematic form one example of a current thin film read element 1110 of a tape head which includes a thin film magnetoresistive (MR) sensor 1112 disposed between two shield layers 1114, 1116. The bottom surface 1118 of the read element 1110 is typically polished to provide a recording surface facing the recording medium, such as a tape 1120. The thin film of the sensor 1112 defines a sensing axis 1122 which is orthogonal to the recording surface 1118 of the read element 1110.
A thin film read element for a tape head such as the read element 1110 may be fabricated using standard film deposition techniques used in the semiconductor industry including chemical vapor deposition, atomic layer deposition, sputtering, plating, and standard processing techniques such as lithography, etching, chemical mechanical polishing, etc. FIG. 12a shows a first shield layer 1114 deposited on a substrate 1200 such as a wafer suitable for thin film deposition. A common shield layer material is permalloy. The layers of the thin film sensor 1112 are deposited on the first shield layer 1114. Depending upon the type of the thin film sensor, these layers may include one or more of magnetic layers including hard and free magnetic layers, intermediate layers, and pinning layers. Additional layers associated with and deposited adjacent to the sensor may include bias layers including hard bias layers, non-conducting layers and current lead layers. Suitable MR sensors include anisotropic magnetoresistive (AMR), giant magnetoresistive (GMR) and tunneling magnetoresistive (TMR) sensors. Deposited on the layers of the thin film sensor 1112 and its associated layers is a second shield layer 1116.
A plurality of read elements similar to the element 1110 may be deposited on the substrate 1200 in this manner. The wafer 1200 may then be diced into pieces to separate the various elements from each other. As represented by the line 1210 (FIG. 12a) one side edge of a piece carrying a read element 1110 may be polished to form a recording surface 1118 as shown in FIGS. 12b, 12c. In this manner, recording heads partially fabricated on a wafer may be diced from the wafer and lapped to provide a row-bar of recording heads. This row-bar may be attached to a flex cable and assembled into an actuator for track-following.
FIG. 13 is a top view of one example of the recording surface 1118 of the read element 1110. The orientation of the gap between the shield layers 1114, 1116 and the orientation of the layers of the sensor 1112 between the shield layers 1114, 1116, defines a sensing axis 1122 (FIG. 12b) between the shield layers 1114, 1116. The sensing axis 1122 is generally parallel to the layers of the sensor 1112 and the shield layers 1114, 1116, and generally orthogonal to the recording surface 1118 (FIG. 11). The shield layers 1114, 1116 are typically formed of a high permeability material and are provided to screen the sensor 1112 from magnetic fields of transitions that are not below the gap between the shield layers 1114, 116. In this manner, the sensor 1112 is substantially sensitive to the vertical component of the magnetic field generated by the media 1120.